Listen Against (Radio 4), the spoof look back at a week in radio presented by Alice Arnold and Jon Holmes, returned last night. And what a glorious episode, structured around Melvyn Bragg's mysterious disappearance.

Arnold reads the news with teensy, devilishly funny tweaks to real bulletin conventions ("as that situation unvelops"). It turns out that Bragghas cracked time travel and is now trying to rewrite history. "Someone has gone back in time and tried to uncancel The South Bank Show," Holmes tells Arnold. Elizabeth the Virgin Queen is no longer so. Everything is being done to tempt Bragg back to now, including dangling Marcus du Sautoy in front of Bragg's vehicle, the In Our Time Machine: "Marcus du Sautoy is like catnip to Melvyn Bragg."

The show swoops on to its targets at a brilliant pace, splicing together words from news headlines to form silly new ones ("Richard Branson to be cut back") and rearranging the words of John Humphrys and David Cameron to suggest their romantic relationship is on the rocks: "Do you want babies?" Humphrys asks; "The right choice is to get married," Cameron replies. Other targets include Fearne Cotton, Alan Carr's laugh and age discrimination at the BBC. The organisation's "Head of Ageism" has to explain why Emilia Fox has been replaced in Silent Witness by Rastamouse.